Friday, June 28, 2013

Reduce start-up delays (IR 89)

Delayed flights which take away slots of punctual flights have a snowball effect. The other flights will be delayed with an IR 89 which stands - in such a case - for a start-up delay.

What if the causer would take the full effect which means that delayed flights can only depart when there is a slot available? As soon as delayed flights have their doors closed they would be put on standby for immediate departure in case of a free departure slot.

Despite the resistance by unpunctual carriers and maybe your hub carrier, your potential is significant.

Want to know your potential to reduce (start-up) delays with this approach? Send us your data and we will tell you.

Sunday, June 16, 2013

Does EUROCONTROL A-CDM improve departure punctuality?

For those who prefer executive summaries, just scroll down.

Don't get me wrong. I am a full supporter of Collaborative Decision Making (CDM) whether it is driven by EUROCONTROL, FAA, SESAR, an airport operator, a local ATC, or even a software vendor. However, CDM, as I understand it, goes beyond data exchange. It is the participation of the airport community when it comes to decisions of the airport about the development of future infrastructure and in daily operation.

According to publicly available information improvements by ECTRL A-CDM include reduced taxi times, fuel savings, better slot adherence, less late gate changes, less network delays, and higher arrival and departure punctuality. The departure punctuality might be the most important element in this list for an airport and its stakeholders. Why? Because airports, airlines and service providers need to allocate reserve capacities for strategic (already planned buffers) and tactical (operational day) delays.

In my recent post about airport punctuality myths I mentioned that I conducted some research about the effect of ECTRL A-CDM on departure punctuality. There were two problems with this. First, as already pointed out in the other post, departure punctuality measured in percent is an imperfect metric. And I am still going to use that impudently. Secondly, there is not much data publicly available.

For the following analysis I used data from the Association of European Airlines (AEA) who themselves receive data from airlines and Central Office of Delay Analysis (CODA). Unfortunately, the data only covers AEA airlines and it does not include passenger figures. But for the sake of this analysis I assume that AEA airlines traffic is the most critical (in terms of turnaround process for instance).

What did I analyze? I investigated all A-CDM Airports according to the DPI implementation status and split them in two categories: (1) Fully compliant (DPI operational) and  (2) Locally implemented. I was expecting the following effect from an A-CDM implementation: (a) sustainable improvement of punctuality after implementation, (b) solid punctuality during adverse conditions (i.e. last winter), (c) continuous improvement, i.e. actual year at least as good as last year with more traffic or better than last year with less traffic and (d) a positive punctuality trend in the last 12 months.

Executive summary:
The following table lists the investigated airports and the findings. Example charts of individual airports can be found below.

In a nutshell:
  • Being an 'A-CDM' airport does not mean that your departure punctuality improves sustainably.
  • Even though the number of flights decreased at most European airports, punctuality has not improved.
  • Most A-CDM airports spiral downwards in adverse conditions, i.e. winter operations.
And one more thing which I noted during the analysis:
  • It is a crying shame that we work in an industry which publishes departure times and at most European airports only about every second flight actually departs on time.
Here are some example charts of the investigated airports. If you would like more of them, just let me know - jweder (at)

Wednesday, June 12, 2013

Three Myths About Airport Punctuality

While Ryanair is boasting to be the most punctual European airline, Oman Air celebrates one day of 100% on-time performance on April 26 this year. Unfortunately there is no public data that proves any of these claims.

What about airports? In April 2011 London Heathrow published a record 94% departure punctuality.  Now they are Britain's worst airport according to the Civil Aviation Authority (CAA).

I think it's time to wade through some of the myths and confusion surrounding airport punctuality.
1. Punctuality is an internationally standardized metric.
Punctuality targets are usually defined in terms of 15-minute punctuality, i.e. a flight is counted as departing on-time if the plane goes off-blocks within 15 minutes of the scheduled time of  departure. But what is "15 minutes"? Is it more than 14'59" or more than 15' or even more than 15'59"? Now some airports and airlines may disagree on this but even ACI, IATA and AEA don't. If they do, then it will probably be 15'59", stealing another minute from the passenger, airline and airport capacity just to look better.

And, have you compared off-blocks times of airport and airline? Some airports check and validate differences within +/- 1 minute, most don't. Result: airport and airline report different punctuality figures.

2. Punctuality is a great metric to benchmark.

In previous posts I was highlighting some flaws of punctuality as a metric.
  • Cancellations of delayed flights improve punctuality
  • Indicator ignores size of aircraft and number of passengers affected
  • No assessment about the financial loss possible
  • Mix of performance which can be influenced with exogenous factors
  • Difficult to determine improvement measures
Why is it still used, even as internal target? Because it is easy to understand and when it is bad, it can be easily attributed to exogenous factors.

3. Eurocontrol A-CDM improves airport punctuality.

There is no evidence that ECTRL A-CDM improves punctuality. Yes, it might reduce taxi times but with a negative effect on departure punctuality. With the lack of evidence I did some research myself and present the findings in my next post.

I know it is easy to lament. What do I have to offer instead? An approach and metrics to actually address the issue together with other stakeholders. Because the airport can have that 360° view and not just the silo view by every other stakeholder.